81900086 has 4 divisors (see below), whose sum is σ = 122850132. Its totient is φ = 40950042.

The previous prime is 81900061. The next prime is 81900097. The reversal of 81900086 is 68000918.

It is a semiprime because it is the product of two primes.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 20475020 + ... + 20475023.

It is an arithmetic number, because the mean of its divisors is an integer number (30712533).

Almost surely, 2^81900086 is an apocalyptic number.

81900086 is a deficient number, since it is larger than the sum of its proper divisors (40950046).

81900086 is a wasteful number, since it uses less digits than its factorization.

81900086 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 40950045.

The product of its (nonzero) digits is 3456, while the sum is 32.

The square root of 81900086 is about 9049.8666288515. The cubic root of 81900086 is about 434.2716238029.

The spelling of 81900086 in words is "eighty-one million, nine hundred thousand, eighty-six".